In the field of Factory Automation (FA) and the like, a visual sensor is used for optically detecting a defect generated in a semi-finished product in the middle of production or in a product before shipment, and/or for optically measuring the size of the defect.
When the detection or the measurement is performed with the visual sensor, it is necessary to properly capture an image of a workpiece. The workpiece is inspected and measured by performing various steps of image processing to an input image obtained by the imaging.
When the visual sensor is used on a production site, it is necessary to properly set an imaging unit, such as a camera, which is included in the visual sensor. The setting of an imaging unit includes, for example, the setting of a view angle of the imaging unit.
A visual field of the imaging unit is determined by an installation posture, such as an angle of the imaging unit. At the production site, when the position of the imaging unit is shifted from the installed position to shift the visual field from a predetermined range, the workpiece no longer fits in the visual field, so it becomes difficult or impossible to perform the inspection and the measurement using the image. Accordingly, in order to return the imaging unit to its original posture, generally the operator checks the image on a monitor, and manually adjusts the installed posture by trial and error until the image of the workpiece is captured in a predetermined position of the visual field.
For example, Patent Document 1(Japanese Unexamined Patent Publication No. 2008-3394) proposes a camera posture adjustment method in order to support the adjustment of the installed posture of the imaging unit. According to the method disclosed in Patent Document 1, tilt information indicating the tilt of the imaging surface of the camera is displayed in order to facilitate the adjustment. In Patent Document 1, the camera is installed on a copy stand (a copy board) so as to be parallel to an original board.